Shift Register Bootstrap Coupling for Gate Driving Circuit Stability
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Solution Overview
Problem
The existing gate driving circuits in display panels face stability issues due to tailing problems in output signals from shift registers, caused by level loss when the output signal transitions from high to low, limiting the application range of these circuits.
Innovation Solution
The proposed solution involves a shift register design with first and second input modules, output modules, and output control modules that use coupling units to manage node potentials and adjust pulse widths, reducing level loss and improving signal stability by coupling node potentials to lower levels when output terminals transition, and periodically pulling down node potentials to maintain signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shift register is used in the gate driving circuit, then the circuit can be implemented with basic components, but the output signal exhibits tailing and level loss affecting stability
Solution Approach 1:
The shift register is divided into multiple stages, each containing separate first and second output modules with independent control. Each stage processes signals independently through different pathways, allowing precise control over signal transitions and eliminating tailing effects without requiring a complete redesign of the entire register structure
Solution Approach 2:
Bootstrap capacitors are introduced as intermediary elements between the output modules and output terminals. These capacitors couple the output signals and provide additional charge during transitions, effectively reducing level loss and eliminating tailing without adding complex control logic to the existing shift register architecture
2Productivity
If the output signal transitions from high to low level, then the signal can change state, but level loss occurs causing tailing and reduced stability
Solution Approach 1:
The bootstrap capacitors are pre-charged during the high level phase before the transition occurs. When the signal needs to transition to low level, the pre-charged capacitors provide the necessary charge to maintain signal integrity, preventing level loss and tailing effects while enabling rapid transitions
Solution Approach 2:
The invention changes the electrical parameters during signal transitions by dynamically adjusting the charge stored in bootstrap capacitors. The capacitors are charged to different voltage levels depending on the signal state, allowing optimization of both transition speed and stability by controlling the charge-discharge cycles
Data Source
AI summary
A shift register, a gate driving circuit, and a display panel. The shift register includes a first input module, a second input module, a first output module, a second output module, a first output control module, and a second output control module, where the first input module is configured to control the potential of a first node according to a first start signal and a first clock signal, the second input module is configured to control the potential of a second node according to a second start signal and the first clock signal, and the second start signal and the first start signal have opposite potentials; the first output module includes a first coupling unit configured to couple the potential of a third node according to the potential of a first output terminal in the case where the potential of the first output terminal jumps.